Nasal Cavities; Tonsils and Pharyngeal Wall

Anatomy Tables for Today's Topic

highly pneumatized bone that contains the ethmoid air cells; forms the fragile medial wall of the orbit

cribriform plate

perforated portion of ethmoid bone on either side of the crista galli

perforated for passage of the olfactory nerves

crista galli

superior midline projection of the ethmoid bone into the anterior cranial fossa; it arises between the cribriform plates

"cock's comb"; anterior anchor point of the falx cerebri

perpendicular plate

midline process projecting inferiorly into the nasal cavity

forms the superior part of the bony nasal septum

superior nasal concha

medial projection of the ethmoid bone from the superolateral wall of the nasal cavity

forms the superior nasal meatus below it and the sphenoethmoidal recess above it

middle nasal concha

portion of the ethmoid bone that projects inferomedially from the lateral wall of the nasal cavity

forms the superior nasal meatus above it and the middle nasal meatus (which overlies the bulla ethmoidalis and hiatus semilunaris) below it

bulla ethmoidalis

rounded elevation on the lateral wall of the nasal cavity

located under cover of the middle nasal concha; middle ethmoidal air cells drain at its apex

ethmoidal air cells

pneumatized spaces (3-18 in number) within the ethmoid bone; located between the orbits

three groups may be identified: anterior (drain into the hiatus semilunaris in the middle nasal meatus), middle (drain onto the apex of the bulla ethmoidalis in the middle nasal meatus), posterior (drain into the superior nasal meatus)

ethmoidal foramen, anterior

opening in the medial wall of the orbit

transmits anterior ethmoidal vessels and nerve

ethmoidal foramen, posterior

opening in the medial wall of the orbit

transmits posterior ethmoidal vessels and nerve

hiatus semilunaris

groove in the ethmoid portion of the lateral nasal wall between the uncinate process below and bulla ethmoidalis above

receives the frontonasal duct anterosuperiorly, opening of the maxillary sinus posteroinferiorly, and the openings of the anterior ethmoidal air cells in between

frontal

the anterior bone of the skull which underlies the forehead

articulates with the parietal bone posteriorly; zygomatic, ethmoid and sphenoid bones inferiorly; maxilla, nasal and lacrimal bones anteriorly; it is formed from two ossifications centers which normally fuse in the midline - if they do not fuse, a midline "metopic suture" is the result

sphenoid

an irregularly shaped bone forming the central portion of the skull

it has many parts, including a body, greater wing, lesser wing and pterygoid plates

body

central part of the sphenoid bone

contains the sphenoid sinuses; attachment point for the wings and pterygoid plates

sphenoid sinuses

pneumatized spaces within the body of the sphenoid bone

usually paired; it drains into the sphenoethmoidal recess of the nasal cavity

spine of the sphenoid

process of bone that projects inferiorly from undersurface of greater wing of the sphenoid

it is the superior attachment for the sphenomandibular ligament

pterygoid process

process that projects inferiorly from the junction of the body & greater wing of the sphenoid bone

it has several parts: lateral & medial pterygoid plates, hamulus, pterygoid fossa, scaphoid fossa; the pterygoid plates are separated by the large pterygoid fossa throughout most of their length, and by the small scaphoid fossa superiorly

lateral pterygoid plate

thin plate of bone that projects posterolaterally from the pterygoid process

it is the attachment site of the lateral & medial pterygoid muscles (lateral pterygoid m. on its lateral surface, medial pterygoid m. on its medial surface)

medial pterygoid plate

thin plate of bone that projects posteriorly from the pterygoid process

it is the attachment of the superior pharyngeal constrictor m. & the pharygobasilar fascia

scaphoid fossa

an oval depression at the superior end of the lateral pterygoid plate

it is the site of origin of the tensor veli palatini m.

pterygoid hamulus

hook-like projection from the inferior end of the medial pterygoid plate

it acts as a pulley for the tendon of the tensor veli palatini m.

pterygoid canal

canal that occurs at the junction of the greater wing, the pterygoid process and the body of the sphenoid bone

it transmits the nerve of the pterygoid canal from the pterygoid region to the pterygopalatine fossa

maxilla

bone forming the midface

it forms the inferior orbital margin and contains the teeth and maxillary sinus

palatine process

shelf of bone that projects horizontally to meet at the midline in the intermaxillary suture

paired; together, they form the roof of the oral cavity (hard palate) and the floor of the nasal cavity

incisive foramen

opening in the midline, posterior to the maxillary incisor teeth

it transmits the terminal branches of the nasopalatine nn. & sphenopalatine aa.; it marks the point of union during development of the primary and secondary palate

mandible

the U-shaped bone forming the lower jaw

contains the inferior teeth; formed from the mesenchyme of the 1st pharyngeal arch, and its muscles are innervated by the nerve of the 1st arch (mandibular division of cranial nerve V)

ramus

the angled portion of the mandible that joins the posterior portion of the body

it rises nearly vertically from the body; the chondyloid process and the coronoid process extend from the superior end of the ramus; the mandibular foramen is located on the medial surface of the ramus; the medial pterygoid m. attaches to the medial surface and the masseter m. attaches to the lateral surface of the ramus

vomer

thin plate of bone forming the posteroinferior part of the nasal septum

articulates superiorly with the perpendicular plate of the ethmoid bone and the body of the sphenoid bone; articulates inferiorly with the palatine processes of the maxilla and the horizontal plate of the palatine bone

temporal

bone forming the lateral side of the skull

temporal refers the passage of time, which is marked by the appearance of gray hair on the side of the head

occipital

the bone forming the posterior surface of the skull

it articulates superolaterally with the parietal bones through the lambdoid suture, anteroinferiorly with the temporal bone and anteriorly with the body of the sphenoid bone

pharyngeal tubercle

projection located anterior to the foramen magnum

attachment site for the superior pharyngeal constrictor m.

palatine

the bone that forms the posterior part of the hard palate

paired; failure of the perpendicular plates to fuse during development leads to a midline defect (cleft palate)

sphenopalatine notch

a notch at the posterosuperior margin of the perpendicular plate of the palatine bone

along with the sphenoid bone it forms the sphenopalatine foramen

orbital process

a small, superior projection from the perpendicular plate of the palatine bone

it forms a small part of the floor of the orbit located posteroinferiorly near the apex

horizontal plate

the portion of the palatine bone that forms the posterior 1/3 of the hard palate

paired; the two horizontal plates meet at the midline

greater palatine foramen

an opening in the hard palate located medial to the 3rd maxillary molar tooth

it transmits the greater palatine neurovascular bundle; it is an important site for oral anesthesia

lesser palatine foramen

an opening in the hard palate located posterior to the greater palatine foramen

there may be more than one; it transmits the lesser palatine n. and vessels

cricoid cartilage

the inferior and posterior cartilage of the larynx; it forms a complete cartilaginous ring; its arch projects anteriorly and its lamina is broad and flat posteriorly

connected: above to the thyroid cartilage via the inferior horn of the thyroid cartilage, to the conus elasticus, to the arytenoid cartilages which sit atop the lamina; connected below to the first tracheal ring via the cricotracheal ligament

connected above to the hyoid bone via the thyrohyoid membrane; connected below to the cricoid cartilage via the inferior horn of the thyroid cartilage; connected posteriorly: to the arytenoid cartilage via the vocal ligament and thyroarytenoid m., to the epiglottic cartilage via the thyroepiglottic ligament; it tilts anteriorly to increase the length of the vocal ligament and raise the pitch of the voice

mucous membrane lining the anterior ethmoid air cells and upper anterior part of the nasal cavity; skin of the lower half of the nose

anterior ethmoidal n. passes from the orbit into the anterior ethmoidal foramen, passes through the cribriform plate, passes anteriorly on cribriform plate, then exits the cranial cavity through the ethmoid fissure into the nasal cavity

eyeball, skin of the nose and medial sides of the eyelids; conjunctiva of the medial sides of the eyelids; mucous membranes of the upper nasal cavity, ethmoid and sphenoid sinuses

the distribution of this nerve is indicated by its name - nasociliary

nasopalatine n.

maxillary division of the trigeminal n. (V2)

no named branches

none

mucous membrane of the nasal septum; mucous membrane of the anterior portion of the palate

nasopalatine n. innervates the mucosa overlying the primary palate (development); it passes through two openings in bone: sphenopalatine foramen and incisive canal

olfactory n.

the filaments of the bipolar olfactory epithelial cells constitute the olfactory n.

second order olfactory nerve cell bodies located in the olfactory bulb

none

smell (SVA)

also known as: CN I, 1st cranial n.; multiple olfactory filaments pass through the cribriform plate to exit the anterior cranial fossa and synapse in the olfactory bulb; the olfactory tract carries the signal from the bulb to olfactory cortex of the forebrain

palatine, greater

maxillary division of the trigeminal n. (V2)

posterior inferior lateral nasal brs.

none

mucous membrane of the inferior part of the lateral nasal wall; mucosa of the hard palate

greater petrosal n. joins the deep petrosal n. to form the n. of the pterygoid canal; the greater petrosal n. contains: preganglionic parasympathetic axons bound for the pterygopalatine ganglion where they will synapse; it passes through the hiatus of canal of greater petrosal n. in the petrous part of the temporal bone

petrosal, lesser

tympanic nerve, from the glossopharyngeal n. (IX)

otic ganglion

secretomotor (preganglionic parasympathetic) for the parotid gland

none

lesser petrosal n. synapses in the otic ganglion and postganglionic axons distribute to the parotid gland by joining the auriculotemporal n.

contains: preganglionic axons of the greater petrosal n. bound for pterygopalatine ganglion where they will synapse; postganglionic sympathetic axons of the deep petrosal n. which will pass through the pterygopalatine ganglion without synapsing

a parasympathetic ganglion; the pterygopalatine ganglion hangs off of the maxillary division of the trigeminal n. (V2) within the pterygopalatine fossa; preganglionic axons of the greater petrosal n. synapse here; postganglionic sympathetic axons of the deep petrosal n. pass through the pterygopalatine ganglion without synapsing (they synapse in the superior cervical sympathetic ganglion)

GSA: skin of the external auditory meatus; GVA: viscera of head, neck, thorax & abdomen proximal to the left colic flexure; SVA: taste from the epiglottis

also known as: CN X, 10th cranial nerve; the vagus n. passes through the jugular foramen to exit the posterior cranial fossa; vagus means "wanderer" in reference to its extensive distribution to the body cavities

trigeminal n.

motor root arises from the trigeminal motor nucleus in the pons (SVE); sensory part arises from the trigeminal ganglion (GSA) and projects into the pons to the primary sensory nucleus of V or more inferiorly to the nucleus of the spinal root of V (medulla and upper spinal cord)

GSA: skin of the lower lip and jaw extending superiorly above level of the ear; mucous membrane of the tongue and floor of the mouth; lower teeth and gingiva of the mandibular alveolar arch

also known as: V3; passes through the foramen ovale to exit the middle cranial fossa; the otic ganglion is associated with the medial side of V3 below the foramen ovale; the auriculotemporal n. carries postganglionic parasympathetic axons to the parotid gland; the submandibular ganglion is associated withe the lingual n. near the submandibular gland; postganglionic parasympathetics from the submandibular ganglion supply the submandibular gland and the sublingual gland

GSA: skin of the upper lip, cheek, lower eyelid; mucous membrane of the palate; teeth and gingiva of the maxillary alveolar arch; the mucous membrane lining most of the nasal cavity; the mucous membrane lining the maxillary sinus

also known as: V2; maxillary division of the trigeminal n. passes through the foramen rotundum to enter the pterygopalatine fossa; the pterygopalatine ganglion is associated with it in the pterygopalatine fossa; postganglionic parasympathetic fibers distribute with branches of the maxillary division to mucous glands of the nasal cavity and palate; the zygomatic n. & its brs. carry postganglionic parasympathetic axons to the orbit to reach the lacrimal n. and lacrimal gland

taste (SVA) from the anterior 2/3 of the tongue; part of the skin of the external auditory meatus

also known as: CN VII, 7th cranial nerve; exits the posterior cranial fossa by passing into the internal acoustic meatus, goes through the facial canal; motor to muscles of facial expression exits the skull at the stylomastoid foramen

the portion of the pharynx located posterior to the palatoglossal arches of the oral cavity and inferior to the soft palate

oropharynx communicates: anteriorly with oral cavity through oropharyngeal isthmus (palatoglossal arch), superiorly with the nasopharynx through pharyngeal isthmus (posterior margin of soft palate), inferiorly with the laryngopharynx at the superior margin of epiglottis; it contains the palatine tonsil which is located in the tonsilar bed (between the palatoglossal arch and the palatopharyngeal arch)

the portion of the pharynx located posterior to the laryngeal inlet and the posterior wall of the larynx

connects: superiorly with oropharynx at the superior border of epiglottis, anteriorly with the larynx through laryngeal inlet, inferiorly with the esophagus at the lower border of the cricoid cartilage; laryngopharynx contains the piriform recesses which are lateral to the aryepiglottic folds